The present invention is directed to a universal apparatus, for holding contoured work-pieces, without the use of individual holding fixtures or templates, while manufacturing operations are being performed on the work-piece. It is directed, more particularly, to a universal apparatus for holding contoured work-pieces in any desired pre-determined contour during the performance of various manufacturing operations, the contour being controlled by a programmable computer.
Devices for holding work-pieces during the performance of manufacturing operations are well known in the prior art. In U.S. Pat. No. 2,729,040 issued Jan. 3, 1956 to Wallace et al., there is disclosed a work-holding plate which can be adjusted to conform to the surface contour of a particular work-piece. The work-holding plate comprises a flexible steel plate with an adjustment mechanism located adjacent to the bottom side of the plate for adjusting the plate's curvature. The work-holding plate is also provided with vacuum chucks for securing the work-piece adjacent to the plate's upper surface.
The adjustment mechanism of the prior art work holder comprises manually operated jack screws which engage the underside of the work-holding plate. Although the device can be contoured to the pre-determined curvature of a work-piece, there is a danger that a work-piece may be deformed from its pre-determined contour as there is no means provided to precisely and repeatedly position similarly contoured work-pieces to the work-holding plate. Moreover, since the work-holding plate is mounted on a base by end attachment means such a device does not allow for a wide range of contour deformation.
This prior art holding mechanism has a number of other disadvantages as well. For example, the use of a flexible spring steel plate does not allow for a wide range of contour deformation. In addition, the use of a screw jack adjusting mechanism which merely engages the underside of the work-holding plate does not have the ability to pull as well as push and thus cannot generate various concave and convex contours.
Another type of prior art holding mechanism that has been proposed is directed to a tape controlled multiple jig arrangement for supporting a built-up surface formed by a series of individual plates. This prior art holding mechanism uses a plurality of spaced, rodlike jigs carried by a support surface. The jigs are adapted for supporting several metal blocks which are built-up in a desired position prior to the welding of the blocks together. A pressurized fluid operated motor and a valve means are associated with each jig for selectively adjusting the height of the jig with respect to the support surface. This holding device is also provided with a control device for feeding control signals to the individual jigs and a perforated tape which carries control signal information for controlling the heights of the individual jigs carried by the support surface.
Although this holding mechanism utilizes a plurality of programmable jigs it has the significant disadvantage of only being able to support a work-piece. For this reason, this holding mechanism is unable to rigidly secure a work-piece and thus would impart undesirable movement to the work-piece during the performance of manufacturing operations. Moreover, the jigs which are used to support the work-piece do not have the ability to pull as well as push and therefore cannot generate various concave and convex contours.
The present invention provides a universal work-piece holding apparatus which overcomes the disadvantages of the prior art devices by providing a lattice type spring metal framework composed of a plurality of vertical flexible supporting bands each interconnected with a plurality of flexible horizontal connecting bands, the spring metal frame being characterized in that it can form a firm contoured support plane over a large area using very few actuator members; it can consequently provide a much greater range of contour deformation. The use of flexible supporting bands each interconnected with a plurality of flexible connecting bands allows for a reduction in the number of programmable actuator members needed for forming a contoured support plane, since each actuator member will cause the deflection of adjoining supporting bands through the action of the connecting bands. This arrangement therefore allows the spring metal frame to form a firm contoured support plane over a large area.
The holding apparatus is also provided with fixed and adjustable index points which precisely orient a work-piece to the position data of numerical or computer controlled equipment performing manufacturing tasks on the work-piece, thereby allowing the user of the apparatus to repeatedly place similarly contoured work-pieces in the same work position without the possibility of inadvertently deforming a work-piece having a different contour.
Accordingly, it is a principle object of the present invention to provide a universal apparatus for holding contoured work-pieces in a pre-determined contour during the performance of various manufacturing operations.
Another object of the present invention is to provide a computer controlled apparatus having the capability to support and precisely orient a contoured work-piece relative to the position data of numerical or computer controlled equipment performing manufacturing tasks on the work-piece.
A further object of the present invention is to provide an apparatus that has a spring metal frame which can form a contoured support plane which corresponds to the pre-determined contour of a particular work-piece.
A still further object of the present invention is to provide an apparatus for holding a contoured work-piece using the combination of a plurality of flexible supporting bands each interconnected with a plurality of flexible connecting bands so that only a limited number of linear actuator members are needed for deforming the spring metal frame to the pre-determined contour of the work-piece.
Still another object of the present invention is to provide an apparatus for holding a contoured work-piece which utilizes a limited number of linear actuator members for forming concave and convex contours.
Another object of the present invention is to provide an apparatus for holding a contoured work-piece which includes means for indexing the contoured work-piece in the contoured support plane of the spring metal frame so as to provide precise and repeatable work-piece positioning.
It is also an object of the present invention to provide an apparatus for holding a contoured work-piece which utilizes a plurality of spaced vacuum cups which can be selectively activated for holding a specific work-piece in the contoured support plane formed by the spring metal frame.
Other objects and various further features of novelty will be pointed out and will occur to those skilled in the art in the following specification when taken in conjunction with the accompanying drawings.